Dry starch product



Patented Mar. 23, 1943 DRY STARCH PRODUCT August Adolph Salzburg,London, England, as-

signor to Dryfood Ltd., London, England,

limited liability company of Great Britain No Drawing. Application April15, 1939, Serial No. 268,023. In Germany April 20, 1938 9 Claims.

The present invention relates to starch products suitable for thepreparation, with cold water and without heating, of blancmanges,puddings, creams, custards and sauces. It is particularly concerned withdry preparations which may contain besides starch, certain additions andwhich, when stirred with cold water, will form suspensions which withina few minutes form jellies which can be cut with a knife and have theconsistency, solidity and stability required of a blancmange.

It is well known that green (natural) starch swells in hot water. Potatostarch, when treated (boiled) with hot water, forms after cooling atoughstringy sticky paste, which is not brittle. The same applies tostarch from other tubers, such as arrowroot starch. Stem starches suchas sago starch behave similarly, although they form considerably lessviscous liquors when boiled with hot water. In contradistinctionthereto, the starches of cereals. for instance maize starch, wheatstarch, rye starch and rice starch, when boiled with water and cooled,are converted into jellies possessing all those properties which arecharacteristic of blancmange, in that they are stable and elastic andcan be cut with a knife, from which they can readily be detached.

Apparently a jelly possesses the solidity, stability and elasticityrequired in a blancmange only if during solidification a kind ofskeleton is formed within the gel substance by the nonhydrolysed partsof the starch-granules, e. g. the envelopes of the granules, andsupports the hydrolysed part of the gel. While potato starch and otherstarches of similar constitution show a tendency to swell too far and tobe reduced to a shapeless mass, maize starch swells much more slowly andonly at higher temperature, and after V the swelling process some of theoriginal granular matter, probably the envelopes of the starch granules,form the elements from which the gel skeleton is being built up. Othercereal starches such as wheat starch and rice starch undergo a similarconversion; they swell readily, but not too far, and therefore deservethe name of natural blancmange-forming starches. Rye starch behavessimilarly, but it may in some cases impart to the dry preparation anundesirable taste or flavor.

I have now found that it is possible to produce from naturalblancmange-forming starches dry preparations which, when mixed with coldwater, solidify to form a blancmange-like jelly. It is surprising thatthese starches, when converted into such dry preparations, retain theirfavourable limited swelling capacity which enables the skeletonmentioned above to be built up.

I have found that such dry preparations can be prepared by firstreducing the starch to a paste with hot water, and thereafter drying thepaste by a process which leaves unchanged the physical structure of thestarting material, so that the dried product, on taking up water again,will swell and in swollen condition will be identical with the swollenstarch (paste), which was subjected to the drying process. The pasteprepared with hot water may for instance be subdivided and dried in thisstate of fine subdivision. Preferably the paste, which, besides starchand water, may contain additional matter, is atomized and rapidly driedat a moderately raised temperature.

The reduction of the starch to a paste (pastification) should be carriedout at a temperature below C. and preferably within the range of 73-88C. Within this range of temperatures there exists for each kind ofstarch an optimum temperature for pastification, at which a paste isobtained resulting in a dry preparation which, when mixed with coldwater, forms a blancmange-jelly possessing the optimum solidity andstability. If reduction of a starch is efiected at a higher or lowertemperature than this 01)- timum temperature, the solidity and stabilityof the jelly forming the blancmange will as a rule be inferior.

With maize starch the optimum temperature is at or near 78 C., i. e.somewhatv below the temperature at which this starch is completelypastified, i. e. the temperature at which the starch molecule will takeup and bind the largest possible proportion of liquid and the starchgranules, while being swollen to the point at which they are about toburst, in their great majority still have retained a recognizableindividual shape and have not yet released their contents of amylose.With wheat starch the optimum temperature of 88 C. is also thetemperature at which complete pastification takes place. The differencebetween the two cases is due to the fact that wheat starch, being lessreadily pastified, must be heated up to complete pastification and thatthe danger of too far reaching swelling and bursting of the starchgranules with consequent loss of the property of forming onsolidification a stable jelly does not exist. The temperature bestsuited for the formation of a satisfactory paste from rice starch is 780., similar as in maize starch. In all cases the onversion of the starchinto a paste must be efiected with relatively largequantitis of wateralso in order to obtain a sufficiently easily flowing paste or a pastewhich can at least be fed to the atomizer or spraying device by means.of a pump. In the case of maize starch which requires about thefour-fold quantity of water, relative to the weight of the starch, inorder to swell completely, a proportion of 6-15 parts by weight of thestarch per 100 parts by weight of the liquid (for instance water) hasbeen found to be suitable. Higher concentrations may be useful if thepaste is fed to the spraying device under increased pressure. Forinstance at a concentration of 10 parts starch and 100 parts liquid apaste isformed, which can easily be fed to a spray-drying device bypumping.

Since it is frequently desirable to add to the dry preparation duringmanufacture additional substances, for instance sugar, cocoa, milk,fruitjuices and the like, it will in certain cases be recommendabletoadd these substances to the paste before it is dried. In that case thephysical properties of the paste may be changed to such an extent thatit may become advisable to operate with a different concentration. Thusfor instance an addition of milk instead of water will increase, theaddition of cane sugar will reduce the viscosity of the paste. Otherkinds of sugar, for instance glucose, fructose and arabinose, actsimilarly to cane sugar. An addition of nonpastified meals, for instancecocoa meal, renders the paste mixture more supple, thus bringing forth asimilar change as a reduction of the viscosity. If additions are madewhich reduce viscosity, the percentage of starch in the mixture may beincreased. On the other hand, if viscosity raising materials are added,a lower concentration of the starch may be chosen in order that thepaste can easily be fed to the dryer and atomized therein.

For instance in order to keep up the easy flow of a paste obtained fromabout '7 kilos maize starch and 100 litres water, if whole milk isadded, the percentage of starch should be reduced to about 5.4 kgs. per100 litres. In order to obtain the desirable proportion of starch tomilk albumen, such a paste may for instance be prepared from 1.35 kgs.starch, litres whole milk and 10 litres water, the maize, starch beingstirred with the water to form a suspension and the whole milk beingadded thereafter. A paste prepared from 1.35 kgs. starch, 1.50 kgs.sugar, 0.275 kg. cocoa, 10 litres water and 15 litres whole milk byfirst boiling the cocoa in water, then addingthe sugar, and then thewhole milk and the maize starch showed the same degree of easy flow.When the paste is fed to the dryer by pumping, it may be formed from1.35 kgs. starch, 215 kgs. sugar, 0.32 kg. cocoa and 10 litres water, inwhich case it contains more than 28 per cent by volume of starch andother constituents. In certain cases the content of dry substances maybe raised to 40-50 per cent by volume.

A relatively higher starch concentration must be chosen if fruit-juicesare mixed with the paste, since this causes a decomposition of thestarch during the production of the preparation and this decompositionwill probably continue in the finished dry preparation. Suchpreparations therefore do not possess the practically unlimitedstability of those which besides starch contain milky substances as wellas cocoa and albumen.

Before the paste is fed to the drying apparatus, it may first behomogenized in a homogenizing apparatu in order to reduce its degree ofviscosity. Homogenization may at the same time increase the supplenessof the paste, butin order to attain this the paste 'must be preventedfrom cooling. As a rule it will suffice if the paste is not allowed. tocool below about 40-50" C. If it has been homogenized; it is recomm' imaintain the temperature, at p has taken pl ip ca I have about tocurrent of hot be removed from the drying a..- a 2---. speed. Theproperties of the jelly which iorms the pudding, depend on the fact thatthe paste is dried in its finest subdivision, giving an optimum surfacearea to the powder thus obtained,

which'enables it to swell in cold water and to form a blancmange-jelly.On principle, any drying method may be used which evaporates the waterin fractions of a second and results in the formation of a powder, theparticles of which possess a sufficient surface area, thus enabling -thepowder mixed with cold water to form a blancmange-jelly. This propertyof swelling is not attained if starch paste is dried comparativelyslowly in scales or lumps and ground after drying. My investigationshave however shown that if a starch paste, which is obtained by treatinga natural jelly-forming starch at a temperature below C. with a quantityof water such that the resulting paste is easy flowing or can beconveyed by pumping, is dried in a state of fine subdivision, theresulting dry preparation, when subsequently brought in contact with andafter having adsorbed, water, will practically be the same product asbefore the drying. Thus the dehydration process, carried through whendrying such a paste under conditions of fine subdivision, is reversiblein that it does not change the constitution of the material except byexpulsion of water, so that the dry preparation can be reconverted intothe starting product by taking up water, i. e., by simple hydration.This fact is characteristic of the new process as distinguished from thedrying of the paste under mechanical action, for instance by compressingthe product between heated metal surfaces or by spreading it on heatedcylinders. Such drying methods have been used for instance in theproduction of potato flakes, but, if applied to starch pastes, would notlead to the formation of preparations fit for conversion with cold waterinto blancmange-jellies.

The drying temperature of the paste particles should not exceed thetemperature at which the paste is prepared, lest the paste particlesmight be injured and particular care should be taken to avoid contact ofthe atomized paste droplets with an air current at a temperature suchthat charring of the paste might arise or the sugar present in thestarch might undergo caramelization.

In certain cases a drying temperature as low as 50-70 C. will besuitable.

When mixing about 11.3 to 15 parts of the dry preparation thus producedfrom maize starch with 100 parts cold water, a blancmange is obtained,in which the solidity and stability of the jelly is about equal to thatof a blancmange produced by mixing 9 parts of the ordinary kind ofblancmange starch with 100 parts of boiling water. If a higherpercentage of water is mixed with the dry preparation creams, custardsor sauces are formed instead of blancmange.

In the preparation of blancmanges from the cold-swelling drypreparations, especially if they are produced from maize or rice starch,lumps may'form on the addition of water. This drawback can easily beavoided by mixing the dry preparation with a finely subdivided solublesolid carbohydrate, for instance with finely powdered sugar which actsas a wetting agent for the cold water or milk. A mixture of 100 kgs. ofa maize starch dry preparation with 40 kgs. powdered sugar has beenfound to be suitable. Similar additions also act favourably in drypreparations which contain besides starch; milk, cocoa and othersuitable ingredients. Wheat starch preparations as a rule do not requirethe addition of a solid carbohydrate since they do not tend to formlumps. Sugar added to thepaste before drying also acts as a wettingagent.

In practicing my invention, I may for instance proceed as follows:

Example 1.0.275 kg. cocoa are boiled in water and cooled by addinglitres whole milk. 1.35 kgs. maize starch are stirred with litres milk.The suspensions of cocoa and starch are mixed with 10 litres water, andthe mixture is heated to 78 C., whereby a paste is formed, which is thenspray-dried with air of 94 C. The dry powder obtained in this operationis mixed with 1.9 kgs. powdered sugar.

Example 2.0.49 kg. cocoa and 0.81 kg. sugar are boiled in 10 litreswater and the suspension cooled by adding litres water. 4.08 kgs. maizestarch are stirred with 27 litres water, the two suspensions are mixedand the mixture heated to 78 C. The paste thereby obtained is spraydriedwith air heated to 150 C. The dry powder obtained in this operation isintimately mixed with 3.74 kgs. powdered sugar. The mixture is dividedin two halves. One half is intimately mixed with 86.71 grams tartaricacid, the other half with 97.29 grams bicarbonate of soda. The twomixtures are then intimately mixed with each other.

Example 3.-0.324 kg. cocoa and 0.405 kg. sugar are boiled in 10 litreswater and cooled by adding another 10 litres water. 1.814 kgs. maizestarch are stirred in 7.5 litres water and mixed with the cocoasuspension, the mixture then being heated to 80 C. whilst stirring, toform a paste which is then spray-dried with air heated to 150 C. To thepowder thus obtained are admixed 1.67 kgs. powdered sugar. To one halfof this mixture are added 39.59 grams tartaric acid, to the otherhalf44.41 grams bicarbonate of soda and the two halves are then mixed again.

Example 4.To 1.36 kgs. rice starch are added 0.6 kg. sugar and themixture is stirred with 27.25 litres water. The mixture is heated to 78C. and stirred to obtain a paste, which is then spray-dried with airheated to 130 C. To the powder resulting/in this operation 700 gramspowdered sugar are admixed.

Example 5.5.445 kgs. wheat starch and 1.134 kgs. sugar are stirred into54.5 litres water. The suspension thus obtained is heated to 88 C. inorder to form a paste, which is then spray-dried with air heated to 140C. The fine powder resulting in this operation is mixed 'with 4.3 kgs.finely powdered sugar.

The preparations made from wheat starch have been found to be at leastequal and in higher concentrations even superior, to preparations madefrom maize starch as far as the solidity of the jelly is concerned. Thisis rather surprising in view of the fact that wheat starch jelliesprepared with boiling water are greatly inferior in quality to maizestarch jellies.

Other materials, for instance cut, dried and ground fruit, preferably inthe form of flakes formed from fruit pulp, or powder obtained by dryingfruit-juices or fruit pulp may be admixed to the dry preparation.

The consistency, moulding and wetting capacity and taste of blancmangesprepared from the dry products according to this invention can beconsiderably improved by the introduction of an inert gas or a compounddeveloping such gas, as for instance bicarbonate of soda and tartaricacid, added to the dry preparation. The constituents of a gas-developingmixture may also be admixed separately to difierent portions of thepaste about to be dried. For instance from 2 to 8 per cent of suchcompounds, calculated on the starch, may be added.

It may be useful to emphasize the fact that in contrast with otherprocesses of preparing cold-water swelling starch, in which starch ismixed with cold water in about equal proportions and dried by sprayingat a high temperature, the present process does not include the step ofdrying starch suspended in cold water. In the present process the starchis heated in water to swell at the temperature optimum specific for thisparticular starch which ranges between 73-88 C. This imparts to thepaste the particular property of forming, after drying, with cold watera jelly of a solidity and stability such as required in a blancmange ora pudding. In this process no decomposition of the starch takes place.The process is a two-stage process in that the starch is first reducedto a paste by heating it with water to a predetermined temperaturebetween 73 and 88 C., and then drying this paste, preferably by sprayingor atomizing with warm air, in such manner as to produce a finelysubdivided powder having the large surface area which enables thispowder to swell with cold water and to yield a jelly of the consistency,solidity and stability required of a pudding or blancmange which can becut with a knife and can easily be detached therefrom.

Various changes may be made in the details disclosed in the foregoingspecification without departing from the invention or sacrificing theadvantages thereof.

I claim:

1. The method of producing cold-swelling preparations from blancmangeorpuddingforming starch which comprises treating the starch at atemperature ranging between about- 73" C. and C. for conversion into apaste with about 6 to 15 parts water per 1 part starch and drying thispaste in a state of fine subdivision.

2. The method of claim 1, in which maize starch is converted into apaste at about 78 C.

3. The method of claim 1, in which rice starch is converted into a pasteat about 78 C.

4. The method of claim 1, in which wheat starch is converted into apaste at about 88 C.

5. The method of claim 1, in which the paste is sprayed, for dryingpurposes, into a hot air current having a temperature ranging betweenabout 50 and C.

6. The method of claim 1, in which there is added to the paste, beforeit is dried, a substance having viscosity-reducing properties.

7. The method of claim 1, in which there is added to the paste, beforeit is dried, a pul- 9. The method of producing cold-swelling verulentsubstance having suppieness-increasing preparations fromblancmange-torming starch properties. which comprises treat the starchat a tem- 8. The method of claim 1, in which the paste perature rangingbetween about 73 and 88 C. is homogenized, before being dried, and thetem- 5 for conversion into a paste with about 6 to 15 perature, at whichthe starch is reduced to a parts water per 1 part starch and drying thispaste, is substantially maintained until the drypaste in a state of timesubdivision. ing process starts. AUGUST ADOLPH SALZBURG.

